Vacuum eye
How to identify that the vacuum glass is still sound? We placed a vacuum eye around a fingernail size made of sodium which is super active with oxygen.
When the internal vacuum degree is constant, the vacuum eye remains unchanged in colour. When the degree of vacuum drops, the vacuum eye starts to change colour and eventually cracks and disappears.
The disappearance of the vacuum eye indicates that the conduction and convection in the glass are significantly increased; it also suggests that the LOW-E film will soon be oxidized, and the radiation heat transfer will be significantly increased; that is, the glass's thermal insulation is failing. Users can monitor the life of their windows at any time through this vacuum eye.
